Technical Field
The present invention relates to a system for optimizing an inter-network shared spectrum, which is configured to dynamically allocate a shared spectrum based on a Closed Subscriber Group (CSG) base station proportion, also relates to a corresponding method for optimizing an inter-network shared spectrum, and falls within the technical field of wireless communication.
Related Art
Recently, with the continuous development of a wireless communication system and the great popularization of an intelligent terminal, requirements of subscribers for data communication services are increasingly high, and corresponding transmission spectrum demands are increasingly high as well. However, spectrum resources suitable for wireless transmission are limited. In order to avoid mutual interference, various countries in the world adopt static spectrum allocation policies at present, some licensed bands are allocated to a certain fixed wireless service for use, and due to the fact that data transmission is carried out on remaining unlicensed bands by virtue of many wireless communication technologies, spectrum resources at this band are quite crowded. On the other hand, monitoring data of a Federal Communications Commission (FCC) shows that the utilization rate of spectra at most of current licensed bands is as low as 15-85%. Particularly, some spectra are not occupied within most of the time, which may cause serious waste of spectrum resources.
In order to improve the utilization efficiency of spectra, people pay more and more attention to research on a dynamic spectrum resource sharing technology, and research on an inter-operator (cross-network) dynamic spectrum resource sharing technology is one of the hot topics.
At present, inter-operator dynamic spectrum resource sharing is mainly implemented by a shared spectrum pooling technology, different operators combine some or all of their owned spectrum resources to constitute a shared spectrum pool, and shared spectrum pool resources are dynamically and reasonably allocated by virtue of a relevant optimization mechanism. Compared with intra-operator dynamic spectrum resource sharing, the inter-operator dynamic spectrum resource sharing technology can effectively relieve imbalance between services of different operators in a specific area, can improve the flexibility and fairness in spectrum resource sharing, can further improve the utilization rate of spectrum resources, and can relieve the problem of shortage of the spectrum resources.
In the prior art, R. H. Kamal, et al., proposed a centralized dynamic inter-operator spectrum sharing solution based on a game algorithm (with reference to PIMRC″09,pp. 425-429). It analyzes a process of competition between different operators by establishing a non-zero sum game algorithm model. A spectrum management entity is shared for centralized management on cell base stations of different operators, and the entity carries out global optimal spectrum resource allocation by analyzing relevant information reported by each cell base station. However, how to ensure the fairness in spectrum allocation and the privacy of interaction information is vital. In view of the sensitivity of interaction information between different operators, it is still hard to share the same spectrum management entity between different operators. V. L. Anchora, et al., proposed an optimized shared spectrum allocation method according to downlink channel selection (with reference to Proc. IEEE ISWCS, pp. 286-290, August 2012). By virtue of results of measuring different channels by different base station terminal subscribers, each base station selects optimal channel resources, in a shared spectrum pool, to be transmitted, thereby improving the efficiency of spectrum resources. However, since optimal channels selected in the shared spectrum pool by each base station are probably overlapped, a great number of signaling overheads will be brought during negotiation for conceding, and the Quality of Service (QoS) of a wireless transmission system is affected. S. Hailu, et al., proposed an adaptive spectrum sharing algorithm between different operators (with reference to Proc. Int. Conf. Cognitive Radio Oriented Wireless Netw., June 2014, pp. 131-135), bandwidths are divided into exclusive bandwidths and shared bandwidths for use, and when having access to a channel, a subscriber preferentially selects an exclusive channel or a shared channel in consideration of inter-network interference intensity.
However, these methods only consider an inter-operator spectrum sharing situation of a base station in a single working mode within the same area. In an actual deployment scenario, base stations in different working modes are usually deployed within an area in a mixed manner according to actual demands. Thus, among base stations probably distributed in different cell clusters within an area, the quantity of CSG-mode base stations and the quantity of OPEN-mode base stations are different. If the same shared spectrum size is set for each cell cluster, average bandwidths of subscribers will be affected, thereby affecting the QoS. On the other hand, a base station can adjust a working mode as needed. For instance, a CSG mode is adjusted to an OPEN mode or the CSG mode is adjusted as the OPEN mode. But if the working mode of the base station is changed, the average bandwidths of the subscribers will be affected, thereby affecting the QoS.